During surgical procedures, particularly when the patient is under or recovering from general anesthesia, it is highly desirable to monitor the carbon dioxide of the breath exhaled by the patient. The amount of carbon dioxide in the exhaled breath, particularly at the end of the respiratory cycle, known as ETCO2, indicates the health of the patient, and can be used to forecast changing conditions of the patient.
The American Society of Anesthesiologists implemented a new standard mandating the use of carbon dioxide (CO2) monitoring during all general anesthesia, whether in or out of the operating room, for both intubated and non-intubated patients. This new standard of care necessitates recognition, support, and compliance by key personnel involved in the management and delivery of anesthesia and procedural sedation. As the use of procedural sedation expands beyond the operating room, implementation of the standard becomes relevant to a broad spectrum of settings including hospitals and ambulatory care facilities as well as office-based practices for medical, surgical, dental, and oral surgery offices. Capnography, the monitoring of carbon dioxide in the patient's expelled breath, significantly reduces patient's safety risks by giving the earliest detection of hypoventilation.
Some authorities indicate that capnography should now be considered an essential component of patient monitoring in all situations in which drugs are given that impact levels of consciousness, responsiveness, and airway protective reflexes.
Qualitative clinical signs such as chest excursion, observation of the reservoir breathing bag, and auscultation of breath sounds are useful. Continual monitoring for the presence of expired carbon dioxide is to be performed unless invalidated by the nature of the patient procedure or equipment.
In addition, monitoring of other aspects of the patient's breath can also be beneficial, such as the detection of certain drugs, alcohol, DNA, antibodies (including tumor), blood sugar, billirubin, acetone, and other elements in organic and inorganic compounds that might be present in the body.
Preferably, the sample of the patient's breath should be collected next to the opening of the larynx at the end of the respiratory cycle so that the tested sample will have minimal dilution from the ambient air, therefore be a truer sample for analysis.
Respiration devices and alarm systems for such devices are known in the art. Alarms are provided for alerting an operator when a patient is not breathing or the patient's breathing is failing outside of a normal breathing pattern. Such respiratory devices that are provided with alarms are disclosed in U.S. Pat. Nos. 3,798,629; 3,802,417; 3,961,627; 4,287,886; 4,366,821; 4,368,740; 4,413,632; 4,417,589; and in my prior U.S. Pat. No. 4,651,746. However, it is desirable to monitor the breath exhaled by the patient at the larynx to provide the evaluation of breath undiluted by ambient air or other conditions of the throat and mouth.
Another desired situation for monitoring exhaled breath is that the intubation device that reaches the larynx should have the ability to perform several functions, such as insufflation of medication directly to the larynx area of the throat, aspiration of mucus from the throat, monitoring of the breath expelled from the larynx area of the throat, and maintaining a continuously open airway for continuous breathing by the patient, all without removal of the oro-pharyngeal airway from the throat. This is particularly important for infants and children of small size because the small change in condition can be traumatic for the smaller body. Early detection of the change in breath condition of the smaller patient might be critical.
It is to these problems and objectives that this invention is directed.